Screw feed centrifugal pump



March 21, 1961 L. M. NECHINE 2,975,714

SCREW FEED CENTRIFUGAL PUMP Filed Nov. 1, 1954 5 Sheets-Sheet 2 March 21, 1961 Filed Nov. 1, 1954 L. M. NECHINE SCREW FEED CENTRIFUGAL PUMP 5 Sheets-Sheet 5 H lllllllllll lllllI' March 21, 1961 L. M. NECHINE SCREW FEED CENTRIFUGAL PUMP 5 Sheets-Sheet 4 Filed Nov. 1, 1954 March 21, 1961 1.. M. NECHINE SCREW FEED CENTRIFUGAL PUMP 5 Sheets-Sheet 5 Filed Nov. 1. 1954 Unimd tates Patent SCREW FEED PUMP Leonard M. Nec'hine, Highland T'aflr, Ill., assignor, .by rnesne assignments, to FoodMachinery and Chemical Corporation, Chicago -Pu1iip 'Conipany Division, San

' Jose, Cali, :1 corporation of Delaware Filed Nov. .11, .-1954,. Ser..-No. 465,935 Ts Claiins. *(ClfifOS -fiil) invention relates .to screw; "feed "centrifugal p mp to'rjpumping liquids "containing "s'o'liilidr seriiisdlid materials and is particularlyc'oneerned withinea'ns ferromininu'tin'g the solid or semisolid material as it is being imped alon with the-liquid, t'o rprevent clo ging dfJthe pump.

The pump is designed particularly for pumping of sewage "and the concomitant com-minutiae 16f the .la'rfger sewage .s'olids, b-u'tis capable of general usefwh'erever "it is necessary to purnpany liquid "whidh contains solid .or seniisolid material and 'cornniinute th'e solids "InaccOrda'nCe withthepresent iiiivention,"thejpump is provided with a .s'c'rewfconveyor 'in, advance of "the impeller, .andthe screw conveyorjis jirovidedwith hardened screw flutes which c'ooperatewith har'dened axial'shear bars "to corn-minute a substantial proportion [of the solid and "semisolid rriate'ria'l fco'ntained in 'the lsewajge "or "other liquid being pumped. 'Thescrew conveyor is .als'o ;pro viile'd with a' lial ribs which serve to throw the 'solitlgand sefnisolid .materials towards "the cutting members. A

2,975,714 Patented Mar. 21,1961

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Figure 1 is a "front elevational viewer apump embodying theinVenticSn; V a

Fig. 2 is a top "plan .view of the pump shown in Fig.

I Fig. 3 "is a cross sectional 'view of the pump, taken along the line 3-3 ofFig. 2;

Fig. 4 is a crossse'ctional view, taken. substantially long the line 4-4 of 3 and showing the rotating involute curved rotating 3blad'e's 'in dotted ,lines; I

Fig. '5 is 'a cross sectional view, taken ,alongline J5;5

d i fii; t

Fig.6 is a cross sectional view/taken along line -66 of liig. 3 a

fFig. 7. is a cross sectional View, taken along line 7--7 of Fig. 3 showing the cog-shaped flange for preventing abrasive'ibearing liguidffrom entering the sealingmeinb'e'r; t

: ,Fig. '8 is a view, 'pa'jrtlyvin .section and partly 'in elevation, showing .the .subassenibly of ,Parts partially vremoved from the"stationa 1 y support and discharge casing;

9 is a .fop view looking downwardly from the plane9-9 dfPigtS, aindparftiillybrdken away to show the main piping connections; I i Big. '10 is :a front :elevation of the plate adjacent and to the left dftheinipfilkgas viewed Fig. 3; Fig. I1 is ia front elevation of'fthegirnpeller face, look irig'to the righhas ViewedjnFig. '3 and V .Fig. "l2is adetail perspective View of'on'e of. the axial shear bars positioned in the conveyor "housing to pooperate with .the screw flutes of the screw conveyor to;cut

the solid and semisdlid material flewinglhroughzthe con;

veyortopreverit entrance of abrasive Lbearinfgliquid '01 -iine .clogginjg material iiito the bearing chamber of the pump. Alcog shapedfiange is p'rovided adjacent 'thesealhierr'ib'er'to 'producea pumping actio'nite'ndingto iriipl the liquid towards the screw land therebyip'reventthe wentrance o fiab'rasive bearing ililqili'd or line flogging; materialintothe sealing rhembe'r.

'Th'esemieshrouded impeller 'is provided with hardened cuttingi'fiutes adapted to cooperate with 'fiXe'd flutes on an adjacent plat'e to provide "a cutting or shearing action Ion any solid, semisolid or s'triri'g ly material whih might enter between "the'inrpfller andtheplate. "Ihe' phteadja'cent the impeller has ,a surface portion "flush with (the iixed iiiu'tes to increase the efficiency (if the counterpumping action inducedby "the impeller'lflut'es ancltalso to aid in preventing the entrance of "material into the lower pressure stuffing box area.

'Another'ife ature: o'f the' puin'p is "that the princjp a1 .wearing parts have renewable surfaces and Joan be removed without affecting thec'o'nn'ection oftlie prinipalrpartsio theusuction and discharge j'pipe lines through whichdhe liquid is brought to the [pump and through which :the liquid is discharged fromth pum 'Hhe various parts are arranged into three sub'ass'eml'alie's which ,may be readily reinovedto leave the stationary support and..suction "housing, and the discharge casing, bolted together with all the removable wearing -sur'faces removed and with the piping tco'nnections unbroken. his arrangementYfacilitatcs replacement .of any =worn part that :requires replacement.

The structure .by means of which.theabove-mentioned and other .advantages of t the invention are attained :will be describedin the-following specification, taken inconjunction with .the accompanying drawings, es'nowing ea preferred illustrative embodiment of the invention, :in

which:

veyorito theinrpe'ller. i p

Referringtothedravvings, the reference numeral 2 indicates a "stationary support and suction housing which is secured "to a suitable fioorby bolts 3, or the like. .An

intake pipe '4 (Fig. is integral with "housing 2. A

dis-charge cas'ingS is secured tohousingzbybolts 61(Fig.

3). .Abrac ketfl is s'ecured'tothe opposite side of dis chargehousing'5' byfrr1eansof boltsgS. "A bearing cap 9 "(F-ig. 3') 's'ecured't'o the end :of bracket 7 by'me'ans of bolts lilhas an opening '11 to'receive ashaft '12. Opening "liis proVided 'withgag'reaseseal -13 'whichjfits closely around :the shaft. Bearing cap 9 is provided with a greasefitting 14-a11'da drainplug 15. Shaft12is oifset near't-he bearing 0.311, as-indicated rat :16, Fig.3, and a ball bearingass'erribly "17 is mounted'onfthe shaft between "oflset T6 and a Flock nut 18. The ball "bearing asseni-bly takes "both r'adi'al and thrust loads.

I fShaft 12 is provided with-another offset 19 adjacent disharge housing "5. A hardenefd renewable :wearing sleevef20n1ounted on the shaft 'abuts offset 19 at one end. 'Theotherend'of sleeve 20 is held in place by a spacerZl which'abuts :aflinger 2'2 at its other 'end. J'Ihe flinger fis secured to shaft 1 12 by a bolt '23. Thebracket 7' is provided with-a cylindrical flange 24 which ispspa'ced outwardlyfrornisleeve20. Thespacebetween sleeve-'20 and flange' 2f4 is {filled "with-packing 25 which isheld in place-bya gland26 at -one'end and a sealing ring 27 at theother end.

Awear plate z8 is 'secure'dto 'the face ofl bracket 7 by means of bolts 28'. Wear pla-te 28 is positioned adjacent :the rearfface 'of:irnpeller. 29 which is keyed to shaft 12 so :as '5 to 'rot'ate therewith :and is kept from -lo'ngitudinal movement :towards: plate "28 I by :means of :a 1 look nut. -30rthreaded 'ontor threadsi 31 cut onithe outer surface of shaft 12 "adjacent offset 19. A plurality of involute curved flutes '32 I extend laterally -fr'orn the :rear surface of impeller :29. A portion of wear "-plate 28 i is also K provide'rhwith involute curved flutes 33- which are 'fixe'd and are'adapte'd: to cooperate With fiiitesSL-Whih rotate-Milli the impeller,.= tolzc'orn'minute any solid Ur -semisolid in'aterial which may enter between the wear plate and the impeller. Another portion 34 of wear plate 28 is flush with the fixed flutes to provide a sealing surface to increase the efliciency of the counter pumping action induced by flutes 32 and to aid in preventing the entrance of material into the lower pressure stufling box area.

A screw conveyor 35 is keyed to shaft 12 adjacent one edge of impeller 29. The screw conveyor is provided with screw flutes 36 for carrying the liquid towards impeller 29 and axial ribs 36' to throw the solid and semisolid materials towards the cutting members. The other end of the conveyor is held against longitudinal displacement by a lock nut 37 threaded on to a thread 38 provided on shaft 12 adjacent the end of suction housing 2. The end of shaft 12 extends beyond screw conveyor 35 and is joumalled in a bearing 39.

Suction housing 2 is provided with a removable liner 40 secured at one end to a wear plate 41 by bolts 42. Renewable cutting blades 43 are secured to liner 40 by means of bolts 44. The cutting edge of blade 43 cooperates with the outer edge of screw flutes 36 to comminute any solid or semisolid material carried by the liquid flowing from intake 4 to impeller 29. As conveyor 35 is rotated axial ribs 36 provide a centrifugal action in the liquid that tends to throw the solid and semisolid material in the liquid towards cutting blades 43 even when the flow is low, and thereby facilitate the comminution of the solid and semisolid material whenever any liquid flows towards the impeller. A throat cutting ring 45 is mounted within the center aperture of wear plate 41 and cooperates .with screw flutes 36 adjacent the impeller to comminute solid and semisolid material in the liquid.

A labyrinth sealing plate 46 is secured to the opposite end of liner 40 by means of bolts 47. The space adjacent the sealing labyrinth is packed with hard fibrous grease. In order to prevent the liquid from flowing into the sealing labyrinth the screw conveyor 35 is provided at its end adjacent the labyrinth with a sealing impeller comprising an integral cog-shaped flange 49 having a scalloped peripheral surface which creates a turbulence at that point tending to throw the liquid outwardly toward flutes 36, and thereby keeps the liquid from entering the joint between the inner edge of plate 46 and lock nut 37. A bearing retaining plate 50, which encloses bearing 39, is secured to the end of liner 40 by means of bolts 51 which pass through labyrinth 46. A grease fixture 52 is secured to the bearing retaining plate to lubricate the portion of shaft 12 within bearing 39.

The operation of the pump is very simple. Liquid, such as sewage, containing solid and semisolid material passes through intake 4 and is carried by screw conveyor 35 to impeller 29. The rotary movement of axial ribs 36' on the conveyor throws the solid and semisolid material towards cutting blades 43 which cooperate with the outer edge of screw flutes 36 to comminute the solid and semisolid material so that the liquid reaching impeller 29 is substantially free of solid and semisolid material. If any solid or semisolid material falls between impeller 29 and wear plate 28 it is comminuted by the interaction of involute curved flutes 32 and 33. The liquid is discharged through discharge housing by the impeller.

' If any part of the apparatus becomes worn or breaks so as to require repair or replacement, it is easily accessible without dismantling the pump casings from the pipe lines. If bolts 8 are removed it is possible to remove bracket 7 along with hearing cap 9, shaft 12, ball bearing assembly 17, flingers 22, packing assembly 2527, wear plate 28, impeller 29, and screw conveyor 35 as a complete subassembly. Bearing 39 and its retaining plate 50 may be removed byremoving bolts 51. The entire liner subassembly, including liner 40, cutting blades 43, throat cutting ring 45, wear plate 41 and labyrinth plate 46 may then be removed as a unit, leaving 4 only stationary support and suction housing 2, and discharge casing 5, with the piping connections unbroken.

While I have described a preferred embodiment of my invention in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many .details may be modified or changed without departing from the spirit or scope of the invention. Accordingly, I do not desire to be restricted to the exact construction described.

I claim: I

l. A screw feed centrifugal pump for pumping liquid containing solid and semisolid material, said pump comprising a suction housing, a discharge casing fixed to said housing, a liner subassembly comprising a liner, cutting blades, and a labyrinth sealing plate insertable into and removable from said housing as a unit, and another subassembly also insertable into and removable from said housing as a unit, said second subassembly comprising a shaft, a screw conveyor keyed to said shaft and having screw flutes adapted to cooperate with said cutting blades to comminute solid and semisolid material in the liquid being pumped, and an impeller keyed to said shaft and operable to pump liquid through said discharge casmg.

2. A screw feed centrifugal pump for pumping liquid containing solid and semisolid material, said pump comprising a suction housing, a discharge casing fixed to said housing, a liner subassembly comprising a liner, cutting blades, a throat cutting ring, and a labyrinth sealing plate insertable into and removable from said housing as a unit, and another subassembly also insertable into and removable from said housing as a unit, said second subassembly comprising a shaft, a screw conveyor keyed to said shaft and having screw flutes adapted to cooperate with said cutting blades and said throat cutting ring to comminute solid and semisolid material in the liquid being pumped, an impeller keyed to said shaft and operable to pump liquid through said discharge casing, and a wear plate adjacent said impeller, the adjacent surfaces of said wear plate and said impeller having involute curved flutes projecting therefrom and cooperating to comminute any solid or semisolid material entering therebetween.

3. In a screw feed centrifugal pump, a suction housing, a removable liner positioned within said housing, a plurality of cutting blades secured to said liner and removable therewith as a unit, a shaft extending through said housing, a screw conveyor keyed to said shaft to rotate therewith, said shaft and said screw conveyor being removable from said housing as a unit, axial ribs integral with said conveyor, said ribs being arranged to throw liquid being pumped towards said cutting blades, and screw flutes on said conveyor to cooperate with said cutting blades to comminute any solid or semisolid material in said liquid.

4. In a screw feed centrifugal pump, a suction housing, a removable liner positioned within said housing. a plurality of cutting blades secured to said liner and removable therewith as a unit, and a bearing retaining plate secured to said liner, said plate holding said liner and cutting blades against removal from said housing.

5. In a screw feed centrifugal pump, a suction housing, a removable liner positioned within said housing, a plurality of cutting blades secured to said liner and removable therewith as a unit, a screw conveyor mounted in said housing, said conveyor having screw flutes adapted to cooperate with said cutting blades to comminute solid and semisolid material flowing along in the liquid being pumped.

6. A screw feed centrifugal'pump for pumping liquid containing solid and semisolid material, said pump comprising a suction housing, a discharge casing fixed to said housing, a liner subassembly comprising a liner, cutting blades, a throat cutting ring, and a labyrinth sealing plate insertable into and removable from said housing as a imit, and another "subassembly also insertable into and removable from said housing as a unit, said second subassembly comprising a shaft, a screw conveyor keyed to said shaft and having screw flutes adapted to cooperate with said cutting blades and said throat clifiting r'ing to comminute "solid and semisolidrnaterial in the liquid being pumped, an impeller keyed to said shaft and operable to pump liquid through said discharge casing, sa'id s'cr'e'w conveyor having a' cog-shaped flange integral with one 'end 'adjacfe'iit said sealing plate operable, upon rotation, to impel liquid' a'w'ay from said sealingplate and thereby prevent=entrance of abrasive bearing.-liquid to said sealing plate. p

7. A screw feed centrifugal pump for pumping liquid containing solid and semisolid material, said pump comprising a suction housing, a discharge casing fixed to said housing, a liner subassembly comprising a liner, cutting blades, and a labyrinth sealing plate, said liner subassembly being insertable into and removable from said housing as a unit, and another subassembly also insertable into and removable from said housing as a unit, said second subassembly comprising a shaft, a screw conveyor keyed to said shaft and having screw flutes adapted to cooperate with said cutting blades to reduce solid and semisolid material in the liquid being pumped, and a cog-shaped flange integral with one end of said screw conveyor, said flange being operable, upon rotation of said conveyor, to impel liquid away from said sealing plate to prevent entrance of abrasive bearing liquid to said sealing plate.

8. A screw feed centrifugal pump for pumping liquid containing solid and semisolid material, said pump comprising a suction housing, a discharge casing fixed to said housing, a liner subassembly comprising a liner, cutting blades, a wear plate, and a labyrinth sealing plate, said liner subassembly being insertable into and removable from said housing as a unit, and another subassembly also insertable into and removable from said housing as a unit, said second subassembly comprising a shaft, a screw conveyor keyed to said shaft and having screw flutes adapted to cooperate with said cutting blades to reduce solid and semisolid material in the liquid being pumped, and a cog-shaped flange integral with one end of said screw conveyor, said flange being operable, upon rotation of said conveyor, to impel liquid away from said sealing plate to prevent entrance of abrasive bearing liquid to said sealing plate, an impeller keyed to said shaft and operable to pump liquid through said discharge casing, saidimpeller and said wear plate being positioned adjacent each other, adjacent surfaces thereof having involute curved flutes projecting therefrom and cooperating to reduce any solid or semisolid material enten'ng therebetween.

9. A screw feed centrifugal pump for pumping liquid containing solid and semisolid material, said pump comprising a suction housing, a discharge casing fixed to said housing, a pair of subassemblies insertable through opposite ends into said housing, one of said subassemblies comprising a bearing and a bearing retaining plate, said other subassembly comprising a shaft having one end supported in said bearing, a wear plate, an impeller adjacent said wear plate, said wear plate and impeller having involute flutes projecting towards each other and cooperating to reduce any solid or semisolid material entering therebetween, a screw conveyor keyed to said shaft, and a labyrinth sealing plate, said bearing retaining plate being secured to sealing plate between said bearing and said conveyor, said conveyor having a cog-shaped flange integral with one end adjacent said sealing plate, said flange being effective, upon rotation of said conveyor, to impel liquid away from said sealing plate to prevent entrance of abrasive bearing liquid into said sealing plate.

10. A screw teed centrifugal pump for pumping liquid containing solid and semisolid material, said pump comprising a suction housing, a discharge casing fixed to said anemia 6 housing, a pair-of subassemblies insertablethrough oppos'it'e ends into said housing, one of said suba'ssemblies comprising a bearing and a bearing retaining plate, said other subassembly comprising a shaft having one endsupported 'in 's'aid bearing, a screw conveyor keyed to said shaft, and

being elfective, upon rotation of said conveyor, to impelliquid away fromsaidsealing plate to prevent entrance of abrasive bearing liquid into said sealing plate.

11. In a screw feed centrifugal pump, a suction housing, a removable liner positioned within said housing, a labyrinth sealing plate adjacent one end of said liner, a bearing and bearing retaining plate secured to said sealing plate and said liner, a shaft having one end extending into said bearing, a screw conveyor keyed to said shaft, one end of said screw conveyor having an integral cog-shaped flange adjacent said labyrinth sealing plate, said flange being eifective, upon rotation of said conveyor to impel liquid away from said bearing and to prevent entrance of abrasive bearing liquid to said sealing plate.

12. In a screw feed centrifugal pump, a suction housing, a removable liner positioned within said housing, cutting blades secured to said liner, a labyrinth sealing plate adjacent one end of said liner, a bearing and bearing retaining plate secured to said sealing plate and said liner, a shaft having one end extending into said bearing, a screw conveyor keyed to said shaft, said conveyor having screw flutes adapted to cooperate with said cutting blades to reduce solid and semisolid material in the liquid being pumped, one end of said screw conveyor having an integral cog-shaped flange adjacent said labyrinth sealing plate, said flange being effective, upon rotation of said conveyor to impel liquid towards said screw flutes, whereby abrasive bearing liquid is kept from said sealing plate. 13. In a screw feed centrifugal pump, a screw conveyor having a plurality of screw flutes to advance liquid from the intake towards the discharge end of the pump, a plurality of cutting blades adapted to cooperate with said screw flutes to comminute solid and semisolid material in said liquid as it is flowing towards the discharge end, and a plurality of axial ribs on said screw conveyor adapted to throw liquid being pumped, along with solid and semisolid material present in the liquid, towards said cutting blades.

14. In a screw feed centrifugal pump, a suction housing, a discharge casing connected to said suction housing, a bearing secured against one side of said suction housing, a shaft having one end rotatably mounted in said bearing, a sealing member protecting said hearing from the liquid being pumped, a screw conveyor having a plurality of screw flutes to advance the liquid towards said discharge casing, an impeller integral with one end of said conveyor adjacent said sealing member to throw the liquid away from said sealing member, thereby protecting said sealing member against entrance of abrasive bearing liquid, a plurality of cutting blades in said suction housing, said cutting blades being adapted to cooperate with said screw flutes to comminute solid and semisolid material present in the liquid, and an axial rib projecting from said conveyor to throw the liquid being pumped, along with said solid or semisolid material, towards said cutting blades.

15. In a screw feed centrifugal pump, a suction housing, a discharge casing connected to said suction housing, a bearing secured against one side of said suction housing.

a shaft having one end rotatably mounted in said bearing,

a sealing member protecting said hearing from the liquid being pumped, a screw conveyor having a plurality of screw flutes to advance the liquid towards said discharge casing, an impeller integral with one end of said conveyor adjacent said sealing member to throw the liquid away from said sealing member, thereby protecting said sealing member against entrance of abrasive bearing liquid, a plurality of cutting blades in said suction housing, said cutting blades being adapted to cooperate with said screw flutes to comminute solid and semisolid material present in the liquid, an axial rib projecting from said conveyor to throw the liquid being pumped, along with said solid or semisolid material, towards said cutting blades, an impeller in said discharge casing, and a wear plate adjacent said last mentioned impeller, the adjacent surfaces of said wear plate and said last mentioned impeller having involute curved flutes projecting therefrom and cooperating to comminute any solid or semisolid material entering therebetween.

References Cited in the file of this patent UNITED STATES PATENTS Yoder Feb. 10, 1931 Bell Jan. 7, 1936 Durdin Feb. 4, 1936 Swenson Mar. 7, 1944 Crawford Dec. 12, 1944 Durdin Mar. 20, 1945 Fuller Ian. 4, 1949 FOREIGN PATENTS Switzerland Jan. 22, 1913 Great Britain Apr. 17, 1927 

